Improvement in balancing-pistons



@Frio LEONARD FINLAY, OF ST. LOUIS7 MISSOURI.

A IMPROVEMENT IN BALANCING-PISTNS.

Specification forming part of Letters Patent No. 118,227, dated August22, 1871.

To all whom it may concern:

Be it known that I, LEONARD FINLAY, of St. Louis, in the county of St.Louis and State of Missouri, have invented a new and useful Improvementin Balancing-Pistons; and I do hereby declare that the following is afull, clear, and exact description thereot', wh ich wi ll enable othersskilled in the art to make and use the same, reference being had to theaccompanying drawing forming part oi this specification.

The invention relates to improvements in balancin g steam or air-pistonsworkin g horizontally; and it consists in Inoviding one or more cavitiesin the :face of the piston at the under side, and admitting steamthereto to act between the piston and the cylinder to counteract theweight. The arrangement also facilitates lubrication.

Figure 1 is an end view of a piston, partly in vertical section; andFig. 2 is a view of the face, also partly sectioned.

Similar letters of reference indicate corresponding parts.

.l provi de one or more (preferably two) cavities, A, in that part ofthe principal packing-ring of the piston which works at the bottom, andsteampassages B leading thereto through the side wal ls,

to which passages I prefer to admit the steam through the spaces D atthe end of the outside packingrings, but it may be admitted in anyapproved way; and I arr-an ge the said passages to have steam admittedfrom one sideof the piston to one cavity and from the other side to theother, so that there will be a constant press ure of steam under thepiston, lifting it from the cylinder, no matter which way it is moving.The employment of the two cavities with passages arranged in this wayprevents the blowing ot' the steam through from one side ofthe pistou tothe other, which would take place if only one cavity with passagescommunicating with both sides were used. This arrangement alsofacilitates the lubrication of the piston, for the steam admitted belowit carries with it considerable moisture.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- The cavities A in the bottom of the pistonpaeking,having passages admitting the steam thereto for counteracting the weightof the piston, substantially as speeiiied.

LEONARD lEINLAY.

Vitnesses DANL. MCFARLAN, J. W. (l. HALLEY.

